10. neural stem cells of the brain and their theraputic potential Flashcards
give one factors that help reduce the risk of Alzheimer’s
good cardiovascular health
where are NSC normally found? and what function may this have?
clustered new to blood vessels
this may maintain NSC quiescence
what are neural stem cells and what do they produce?
they are tissue specific stem cells that generate neurons, oligodendrocytes and astrocytes
in comparison to neurons, how many astrocytes are there in the brain?
there are ten times as many astrocytes as there are neurones in the brain
what do oligodendrocytes do?
they en-sheath axons to allow for fast nervous transmission
what cell type are attacked in MS?
oligodendrocytes
can oligodendrocytes be made in the adult brain?
yes
in early stages of development, part of the rapidly dividing ball of cells is given signals to become brain and not … ?
skin
development is coordinated by surrounding tissue. what type of signal defines the front from the back of the embryo?
morphogen gradients
once the potency of developing embryos CNS is down to neural stem cells, what happens?
neurones are generated in the correct place at the right time. these migrate to their final position. glial cells are produced. synapses are generated and excess neurones are culled.
what occurs in the brain throughout life?
remodelling and fine tuning, new synapses are formed and synapses the brain decides not to keep are lost
in early development, what are dopaminergic neurons made from?
radial glia
in early development, where are radial glia?
radial glia span the neural tube
what is the ventral filled with and what is this like in early development?
it is filled with cerebral fluid, it is very larger in early development
once radial glia have made enough dopaminergic neurones they switch to making what type of cell?
they make glia which support the dopaminergic neurones
describe how dopaminergic neurones are produced in early development?
radial glia exit the cell cycle at the ventricular zone and become DN, they wriggle down radial glia to their final position at the edge of the ventricle of the normal tube and grow axons into the forebrain
why is it important to know what transcription factors regulate development?
so that we can copy it in a dish and direct ESC/iPSC into neurons
what two methods can be used to see what transcription factors are being expressed?
FISH and transcriptome analysis (RNA-seq)
why is there post-natal development in the brain?
for memory formation
why is it very hard to generate new neurones in most of the post-natal brain?
during the course of evolution cell division in the brain has been stopped in most regions to reduce the risk of cancer
in what two regions of the brain has the brain decided it is worth the risk of post-natal neuronal development to occur?
striatal subventricular zone (SVZ) and subgranular zone (SGZ)
where is the subgranular zone located?
in the hippocampus
what are the neural stem cells of the subventricular zone?
they are a type of glia
neural stem cells of the subventricular zone have cilia, what it their function?
they have wafting cilia that wash away the waste in our brain as we sleep, this may be why lack of sleep kills
when are the subventrciular zone neural stem cells located?
either directly in contact with or just below the ventricle
what do subventricular zone stem cells become? following this, what can be observed in rodents?
neuroblasts migrate in chains through the rostral migratory stream to the olfactory bulb where they form functioning circuits
what else can NSC of the SVZ make?
oligodendrocytes
why do rodents have a large olfactory bulb and what is the human olfactory bulb like?
rodent rely on smell much more than we do
the human olfactory bulb is shrivelled and basic
when neuroblasts reach the olfactory bulb of rats, what do they become?
GABAergic and dopaminergic interneurons
has an rostral migratory system ever been identified in humans?
no
what do the neuroblasts of the SVZ in humans become? and where do they go?
striatal interneurons
they go to different regions of the brain that is not the olfactory bulb
why is the progeny of these SVZ neuroblasts clinically relevant?
- striatal interneurons are depleted in Huntington’s
- something in about these cells are venerable in this disease
what does a transcription factor programme do in development?
narrow down the potency of a cell
what sort of information is important for the adult neural stem cells of the SVZ?
positional information
this information is integrated from all axis
what can be used to follow the daughter cells of SVZ NSC? and what did the use of these identify in rats?
genetic labels
these identified four new subtypes of interneurons produced in a specific micro-domain of the SVZ
smell and memory is very important to rodents. how many new neurons do they produce a day?
20,000-30,000
how do the NSC progeny differ in from embryonic and neonatal NSC progeny?
they have delayed firing and they are more excitable
what is the hippocampus important form?
new memory formation
what are the two potential fates of memories formed in the hippocampus?
the brain will decide to remember them or forget them if it does not think you will need them in the future